JPS6140938Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distributed fuel injection pump used in a multi-cylinder internal fuel engine.

Furthermore, the present invention has been made with the aim of simplifying the structure and reducing the size and weight of such a distribution type fuel injection pump. By reciprocating the plunger within the hole, the fuel in the fuel pressurizing chamber formed on the top surface of the plunger can be transferred under pressure, while the plunger is moved in the fuel chamber formed in the middle part of the plunger insertion hole. An annular valve formed on the outside of the plunger that is capable of opening and closing an oil hole formed across the top surface and side peripheral surface of the plunger is fitted so as to be rotatable and slidable relative to the plunger. The fuel injection timing can be controlled by displacing the annular valve in the axial direction of the plunger while controlling the fuel injection amount by appropriately rotating the plunger relative to the plunger and changing the opening/closing timing of the plunger. Further, a distribution rotor fitting portion having a cylindrical outer circumferential surface is formed at one end in the axial direction of the pump casing, and on the outer circumferential surface, the distributing rotor fitting portion is arranged at equal intervals in the circumferential direction and one end thereof is disposed on the outer circumferential surface. The other ends of the plurality of distribution oil passages connected to the fuel injection valves provided on the cylinder side and the other end of the main high pressure oil passage whose one end communicates with the fuel pressurizing chamber are respectively opened, while the distribution rotor The fuel pressurizing chamber and each of the distribution oil passages are sequentially and selectively connected to the outside of the fitting part through the main high pressure oil passage by being rotated relative to the distribution rotor fitting part. A cylindrical distribution rotor having distribution grooves formed on its inner circumferential surface that act to communicate with each other is fitted coaxially so as to be relatively rotatable, and a cam for causing the distribution rotor to reciprocate with the plunger. It is characterized in that it can be rotated synchronously with the shaft, and that the structure can be simplified, and the size and weight can be reduced.

Hereinafter, the distribution type fuel injection pump of the present invention will be explained using a distribution type fuel injection pump Z for a four-cylinder diesel engine shown in FIGS. 1 to 4 as a practical example. As shown in Figure 2, there is a fuel pressurizing part A for pressurizing the fuel, and four fuel injection valves (not shown) installed on the engine body side to inject high-pressure fuel pressurized by the fuel pressurizing part A. It has a fuel distribution part B for sequentially pumping fuel to the fuel tank.

The fuel pressurizing part A includes a plunger 2 that is slidably inserted into a bushless type plunger insertion hole 18 formed in the axial center of the pump casing 1;
It has an annular valve 3 which is relatively rotatably and slidably fitted into the fuel chamber 14 formed in the middle part of the plunger fitting hole 18 on the outside of the plunger 2. By reciprocating the plunger 2 using the cam 24 and the spring force of the plunger spring 29, the fuel in the fuel chamber 14 is passed through the oil passage hole 38 formed in the plunger 2, and is fed to a fuel filler formed on the top surface of the plunger. The air is sucked into the pressure chamber 15, pressurized, and then fed under pressure to the delivery chamber 17 via the delivery valve 5.

In the fuel injection pump Z of this embodiment, four protrusions 24a, 2 are provided on the outer peripheral surface of the cam 24.
4a are formed at equal intervals in the circumferential direction, so that the plunger 2 is reciprocated four times for each revolution of the camshaft 11. 4 for each rotation of this camshaft 11
The fuel fed under pressure is supplied to a fuel distribution section B, which will be described later.
The fuel is distributed to four distribution oil passages and sequentially supplied to each fuel injection valve (not shown) attached to four cylinders (not shown) of the engine body.

The annular valve 3 has an outlet 38a (inclined lead part) connected to the oil passage hole 38 of the plunger 2 on one side of its side peripheral surface 3a.
An oil escape hole 40 that communicates or does not communicate with the annular valve 3 is provided through the oil escape hole 40 in the radial direction.
A vertical groove 44 extending in the axial direction of the annular valve 3 and a lateral groove 45 extending in the circumferential direction are formed at these positions. The vertical groove 44 and the horizontal groove 45 each have one side 1 of the pump casing 1 with the fuel chamber 14 in between.
The eccentric head 31 of the metering pin 30 attached from the a side and the eccentric head 33 of the timer pin 32 attached from the other side 1b are respectively fitted. This fuel injection pump Z has metering pin 3
0 to rotate the annular valve 3 appropriately relative to the plunger 2, and change the timing of communication between the oil passage hole outlet 38a of the plunger 2 and the oil escape hole 40 of the annular valve 3. By controlling the injection amount and appropriately rotating the timer pin 32,
The fuel injection timing is controlled by displacing the annular valve 3 in the axial direction of the plunger.

Note that fuel is supplied into the fuel chamber 14 by the feed pump 22 through the fuel passage 50.

The fuel distribution part B is coaxially fitted to the cylindrical distribution rotor fitting part 43 formed at the lower end 1c of the pump body 1 and to the outside of the distribution rotor fitting part 43 so as to be relatively rotatable. By rotating the distribution rotor 4 relative to the distribution rotor fitting part 43, the high-pressure fuel in the fuel pressurizing chamber 15 is transferred to the engine body side as described later. The fuel can be sequentially supplied to four fuel injection valves.

The distribution rotor 4 is fitted on the outside of the distribution rotor fitting part 43 of the pump casing 1 as shown in FIGS. It is meshed with the drive gear 13, and as the camshaft 11 rotates, it is rotated in synchronization with the camshaft 11 on the outside of the distribution rotor fitting portion 43.

Note that the rotation ratio between the camshaft 11 and the distribution rotor 11 is as follows:
In this embodiment, the ratio is set to 1:1. or,
This distribution rotor 4 has a high-pressure oil circumferential groove 53 (hereinafter referred to as a first high-pressure oil circumferential groove 53) formed in the outer circumferential surface 43a of the distribution rotor fitting part 43 in the middle part of the inner circumferential surface 4a.
), a high-pressure oil circumferential groove 54 (hereinafter referred to as a second high-pressure oil circumferential groove 54 ) that communicates with each other in superposition, and a distribution groove 5 that communicates with the second high-pressure oil circumferential groove 54 and extends in the vertical direction.
5. On the other hand, the distribution rotor fitting part 4
The first high-pressure oil circumferential groove 53 on the third side is a high-pressure oil passage 5 formed by vertically penetrating inside the pump casing 1.
2 (hereinafter referred to as the second high pressure oil passage 52) and a high pressure oil passage 51 (hereinafter referred to as the first high pressure oil passage 51) provided through the delivery holder 6. ing. From this delivery chamber 17, it passes through a first high-pressure oil passage 51, a second high-pressure oil passage 52, and a first high-pressure oil circumferential groove 53 formed in the pump casing 1, and then a second high-pressure oil circumferential groove 54 on the distribution rotor 4 side. A series of high-pressure oil passages passing through and reaching the distribution groove 55 will be referred to as a main high-pressure oil passage 56 below.

On the other hand, on the outer circumferential surface 43a of the distribution rotor fitting portion 43 and at a position above the first high pressure oil circumferential groove 53, the distribution groove 55 is formed as the distribution rotor 4 rotates.
Four vertical grooves 60, 63, 6 that alternatively communicate with
6 and 69 are formed at equal intervals in the circumferential direction.
Further, each of the vertical grooves 60, 63, 66, and 69 communicates with oil holes 61, 64, 67, and 70 that open in the upper end surface 1d of the pump casing 1, respectively. These mutually communicating vertical grooves 60 and communication holes 61, vertical grooves 63 and oil holes 64, vertical grooves 66 and oil holes 67, and vertical grooves 69 and oil holes 70 are connected to each cylinder (not shown) on the engine body side, respectively. In the following, the first distribution passage 59, the second distribution passage 62, the third distribution passage 65, and the fourth distribution passage will be described in order. It is called oil route 68.

In addition, these distribution oil passages 59, 62, 65, 68
High-pressure pipe joints 28, 28, . . . are hinged to the open ends on the upper end surface 1d side of the pump casing, respectively.

Furthermore, the second high-pressure oil circumferential groove 54 and each vertical groove 60, 63, 66 on the inner circumferential surface 4a of the distribution rotor 4,
69 in the vertical direction, the inner circumferential surface 4a
An upper circumferential groove 72 and a lower circumferential groove 73 are formed along. Furthermore, the upper circumferential groove 72 and the lower circumferential groove 7
3 are communicated with each other through a communication hole 74 formed in the distribution rotor peripheral wall 4b, and communicated with the fuel chamber 14 through an oblique hole 75 formed in the pump casing 1.

This upper circumferential groove 72, lower circumferential groove 73, and communication hole 74
A series of communication passages including the diagonal holes 75 and 75 are hereinafter referred to as leak oil return passages 71.

Note that the distribution rotor 4 is prevented from falling off by a falling-off preventing member 27 provided at the lower end portion 43b of the distribution rotor fitting portion 43.

The fuel injection pump Z configured as described above is removably fastened to a pump mounting portion 48 provided on the side wall 47 of the engine body using mounting bolts 20, 20, . . . .

Next, the operation of the fuel injection pump Z of the illustrated embodiment will be explained. When the camshaft 11 rotates, the plunger 2 is rotated by the projections 24a, 24a, . . . Each time the fuel chamber 14 is rotated and reciprocated, the fuel in the fuel chamber 14 is sucked into the fuel pressurizing chamber 15, pressurized, and forcefully fed from the delivery chamber 17 through the main high pressure oil passage 56 to the distribution groove 55 side. As the distribution rotor 4 rotates, the high-pressure fuel fed to the distribution groove 55 side is transferred to the first distribution oil passage 59, the second distribution oil passage 59, which selectively communicates with the distribution groove 55 in sequence.
The fuel is supplied to each fuel injection valve (not shown) attached to each cylinder of the engine body through the distribution oil passage 62, the third distribution oil passage 65, and the fourth distribution oil passage 68.
At this time, leaked oil leaked from the main high-pressure oil passage 56 or each distribution oil passage 59 , 62 , 65 , 68 into the sliding contact area between the distribution rotor 4 and the distribution rotor fitting part 43 is removed from the leak oil return passage 71 . The fuel is extracted through the upper circumferential groove 72 and the lower circumferential groove 73 and is circulated back to the fuel chamber 14 side.

The amount of fuel to be injected is determined by rotating the metering pin 30 using a suitable governor to control the annular valve 3 through the plunger 2.
The fuel injection timing is controlled by rotating the timer pin 32 using an appropriate timer to move the annular valve 3 in the vertical direction.

In addition, in FIG. 2, reference numeral 81 is a lubricating oil passage.

Next, to explain the effects of the present invention, the distribution type fuel injection pump of the present invention controls the fuel injection amount and injection timing by simply rotating or vertically moving an annular valve fitted on the outside of the plunger. At the same time, the distribution of fuel can be controlled by fitting a distribution rotor having a distribution groove on the outside of a distribution rotor fitting part formed in the pump casing, and rotating the distribution rotor synchronously with a camshaft. Therefore, it has a simpler structure than the known face cam type distribution fuel injection pump, etc., and has a small body diameter, which has the practical effect of easily promoting miniaturization and weight reduction. It is something.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a distribution type fuel injection pump according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of FIG. 1, FIG. 3 is a vertical cross-sectional view of FIG. It is a - arrow direction view of FIG. 1...Pump casing, 2...Plunger,
2a... Top surface of the plunger, 2b... Side peripheral surface of the plunger, 3... Annular valve, 4... Distribution rotor, 4
a... Inner peripheral surface of distribution rotor, 11... Camshaft, 1
4...Fuel chamber, 15...Fuel pressurization chamber, 18...Plunger insertion hole, 38...Oil passage hole, 40...Oil escape hole, 43...Distribution rotor fitting part, 43a...Distribution rotor Outer peripheral surface of fitting portion, 55...Distribution groove, 56...
...Main high pressure oil passage, 59, 62, 65, 68... Distribution oil passage.

Claims (1)

[Scope of utility model registration request] By reciprocating the plunger 2 in the plunger insertion hole 18 formed in the pump casing 1, the fuel in the fuel pressurizing chamber 15 formed on the top surface 2a of the plunger 2 can be pumped, An oil passage hole 38 is opened and closed, which is formed outside the plunger 2 in the fuel chamber 14 formed in the middle part of the plunger insertion hole 18, and extends over the top surface 2a and side circumferential surface 2b of the plunger 2. The annular valve 3 thus constructed is fitted into the plunger 2 so as to be rotatable and slidable relative to the plunger 2, and the annular valve 3 is appropriately rotated relative to the plunger 2 to open the oil passage hole 38 of the plunger 2. The fuel injection timing can be controlled by displacing the annular valve 3 in the plunger axial direction while controlling the fuel injection amount by changing the opening/closing timing, and further,
A distribution rotor fitting part 43 having a cylindrical outer circumferential surface 43a is formed at one end in the axial direction of the pump casing 1, and disposed on the outer circumferential surface 43a at equal intervals in the circumferential direction, and one end thereof is connected to a cylinder. a plurality of distribution oil passages 59 connected to fuel injection valves provided on the side;
The other ends of 62, 65, 68 and the other end of the main high pressure oil passage 56 communicating with the fuel pressurizing chamber 15 are opened, respectively, while the distribution rotor fitting portion 4
3, the fuel pressurizing chamber 15 and each of the distribution oil passages 59, 62, 65 are connected to the fuel pressurizing chamber 15 through the main high pressure oil passage 56 by being rotated relative to the distribution rotor fitting part 43. A cylindrical distribution rotor 4 having a distribution groove 55 formed on its inner circumferential surface 4a that acts to sequentially and selectively communicate with the distribution rotor fitting portion 43 is coaxially connected to the distribution rotor fitting portion 43 so as to be rotatable relative to the distribution rotor fitting portion 43. A distribution type fuel injection pump, which is fitted onto the top of the pump, and further configured to allow the distribution rotor 4 to rotate in synchronization with a camshaft 11 for reciprocating the plunger 2.